Multiple factors have led to a major push worldwide to reduce electricity demand. These include the recognition of global warming regardless of cause; industrialization of third world countries creating huge increases in electricity demand and fossil fuel consumption, with the obvious economic and pollution problems associated; and increasing electricity prices within industrialized nations as overburdened electrical grid systems incur higher generation costs and struggle to match demand. During the last decade, there has become an increasing recognition that lighting systems are responsible for a substantial proportion of the total electricity consumed by homes and businesses (in the region of 20-25%).
Incandescent light bulbs are well understood and have been in existence since their commercialization in the late nineteenth century. All forms of incandescent light bulbs waste a substantial percentage of the electricity they consume in the generation of heat, rather than light. A major initiative to reduce overall electricity consumption has been the drive to increase the efficiency of light bulbs and reduce the energy wasted in heat. Compact Fluorescent Lights (CFLs) were introduced as part of this initiative. However, while CFLs significantly reduce the electricity consumption compared with an equivalent (lumens) lighting level of incandescent bulbs, they have drawbacks such as the “warm up” time they require before producing their full light output, the harsh/cold (spectrally deficient) light they emit, and the use of toxic mercury in the manufacturing process causing environmental handling and disposal problems.
More recently, semiconductor light emitting diode (LED) based lights have been introduced. While LED light bulbs are currently more expensive than incandescent or CFL bulbs, they have much longer operating lifetimes. LED light bulbs have typical operational lifetimes of 30,000 hours or more, compared with CFLs at around 8,000 hours and incandescent light bulbs at around 1,000 hours.
The initial adoption of LED light bulbs has been slow due to their high price as a result of costly manufacturing (passed on to consumers) when compared to incandescent and CFL bulbs, and the expensive and complex thermal management components required to dissipate the heat generated and maintain the electronic components in the bulb within their operational range. In particular, unlike the filaments in incandescent bulbs or the electrodes in CFL bulbs, LEDs are manufactured using a semiconductor fabrication process. However, LED light bulbs are typically assembled in the same manner as incandescent and CFL light bulbs and these processes are not well suited to the assembly processes usually employed for printed circuit board (PCB) assemblies such as those used in high volume consumer electronics and the like. For instance, typical LED based bulb implementations frequently use simple insulated attachment wires to interconnect the LED driver control electronics, typically mounted on a standard but separate PCB, to the LEDs associated with the illumination functions of the bulb, which are typically mounted on a separate thermally efficient PCB. This connectivity method is highly inefficient, potentially unreliable, labor intensive, and an impediment to automated assembly.
Moreover, like all semiconductor devices, LEDs generate significant heat during operation, and will eventually be damaged or destroyed if the heat buildup is not constrained. LEDs are relatively small die area devices, and driven by relatively high current loads to produce the light output required. This leads to high point-source heat generation from the LEDs, and poses severe heat dissipation issues. Additional electronic and semiconductor components are required to control the power supply and drive current to the LEDs. These components also generate heat and need to be temperature controlled. Further, as the LED temperature increases, both its light output (lumens) for a given electrical current and its operating lifetime are significantly reduced. Therefore, it is paramount that the LEDs are adequately cooled.
Minimization of heat has never been a major focus in incandescent or CFL lighting since heat has always been a byproduct of the light generation process. Domestic and commercial electrical light fittings have simply been designed to deal with the heat generated by these bulbs. However, when considering integrating additional high technology capabilities into a light bulb using semiconductors, for instance, heat becomes of paramount concern. Those of ordinary skill in the art will recognize that heat is one of the key enemies in the construction of high density, small form factor, high technology electronics products.
Typically, early generation LEDs used in LED-based lights were either inefficient and/or chosen for the lowest possible cost, and therefore they generated significant heat. Hence, LED bulbs typically required large expensive heatsinks and complex thermal management to dissipate the heat generated to maintain the electronic components in the bulb within their operational range. Such heatsinks are mounted on the exterior of the bulb near the base, rendering this area unusable for illumination from the bulb. This then reduces the overall illumination effect of the bulb, especially when the bulb is required to replicate the broad, even, spherical radiated light pattern of an incandescent light bulb. This also tends to make LED bulbs less aesthetically appealing and much heavier than the bulbs they replace, and in some case makes them unsuitable for some existing lighting enclosures and fittings.
In order to produce an optimal semiconductor LED based bulb, as well as an LED bulb which can wirelessly communicate with a remote entity (also referred to herein as a “LED smart bulb,” “intelligent wireless LED light bulb,” or “smart bulb”), which meets the goal of easy assembly in mass quantities using automated robotic assembly techniques, and the use of more cost effective design and materials that result in a closer resemblance, both in terms of illumination pattern and physical appearance, to the incandescent light bulb, a different approach is required.
These and other limitations are solved by the present disclosure in the manner described below.